A mini review on biotransformation of coal to methane by enhancement of chemical pretreatment

Coalbed methane (CBM) has great environmental and economic values in addition to its energy content. For years natural gas has been considered a transitional cleaner energy source as it emits less carbon dioxide and other pollutants than other fossil fuels. Due to thebiogenic origin of CBM in many reservoirs, microbial enhancement may also be used to stimulate gas production in coal seams; however, the CBM output is relatively low when compared to other sources of natural gas. Studies have shown that chemical pretreatment of coal prior to gas production can significantly increase the bioconversion rate of coal. This review summarizes and discusses the mechanisms of coal biotransformation and biodegradation in the context of CBM production using chemical pretreatment methods, as well as the latest development in the field, in order to promote the further development of CBM resources.